More concrete was removed with small excavators. Heavier equipment would have sped things up somewhat, but Kashani says the TTC was limited by the overhead streetcar wires. Any construction vehicles tall enough to disturb those wires would have been more trouble than they were worth.

There were three layers of concrete at the intersection: surface, infill, and foundation. A challenging aspect of the job for Kashani and his workers was that all three layers were bonded together. They couldn't remove the top without also removing the foundation.

After the rails were installed, the workers poured a layer of concrete infill to lock everything into place. This time, rather than allow the infill to bond with the foundation, they poured the two layers separately.

The separation between the two layers will make future track-replacement work at the intersection easier, because it will be possible to excavate without damaging the foundation. In two or three decades, when Kashani expects the TTC to replace the tracks again, it might not take quite so long.

After the track work was complete, the workers began to repave the stretches of road they had dug up. Queen and Spadina's concrete crosswalks have been replaced with asphalt ones, because current municipal construction standards call for that.

The intersection of Queen Street and Spadina Avenue reopened today after being closed for two weeks while TTC construction crews replaced the streetcar tracks there.

As one of only three intersections in the city where streetcars need to turn in all eight possible directions (the other such intersections are King and Bathurst and King and Spadina), Queen and Spadina presented unusually complex engineering problems.

Mohammad Kashani, a project engineer for the Spadina track-replacement effort, talked to us about the process of overhauling the intersection. For step-by-step details, check out the (mostly) chronological gallery of the work, above. All the information is in the captions.